Owen Sowerwine contains a mix of black cottonwoods, water birch, and other riparian species at the confluence of the Flathead and Stillwater rivers. Situated on the outskirts of the fast-growing city of Kalispell, this 179-hectare parcel of wildlands is the first officially designated Natural Area on school trust lands in Montana. The license to manage the site is held by Montana Audubon, which completed a master conservation plan that was approved by the State Land Board in January 2003. Owen Sowerwine is the first IBA in Montana to have an approved conservation plan http://mtaudubon.org/pdf/OS%20Master%20Plan%20Body.pdf .
Volunteer birders from Flathead Audubon detected 80 species of birds during annual breeding-season surveys conducted from 1992 to 2000. At least 65 species breed here, including 24 that are of State conservation concern (e.g., Red-naped Sapsucker, Pileated Woodpecker, Willow Flycatcher, Red-eyed Vireo, and Lazuli Bunting). The site also has a small colony of Great Blue Herons, and a resident pair of Bald Eagles nests less than 2 km from the IBA boundary.
Being adjacent to a fast-growing urban area, the site is receiving increasing use from humans and is being encroached upon by housing developments. Horses have trespassed onto the area and damaged native vegetation, and invasive weeds are a problem.
The site is owned by the Montana Department of Natural Resources and Conservation and is part of the Stillwater State Forest. It is managed by Montana Audubon as a State Natural Area.